Diethylpropion

What it is used for

Diethylpropion hydrochloride is indicated in the management of exogenous obesity as a short-term adjunct (a few weeks) in a regimen of weight reduction based on caloric restriction in patients with an initial body mass index (BMI) of 30 kg/m 2 or higher and who have not responded to appropriate weight reducing regimen (diet and/or exercise) alone. Below is a chart of BMI based on various heights and weights. BMI is calculated by taking the patient’s weight, in kilograms (kg), divided by the patient’s height, in meters (m), squared. Metric conversions are as follows: pounds divided by 2.2 = kg; inches x 0.0254 = meters.

The usefulness of agents of this class (see CLINICAL PHARMACOLOGY ) should be measured against possible risk factors inherent in their use such as those described below. Diethylpropion hydrochloride is indicated for use as monotherapy only.

How to take it

Diethylpropion hydrochloride immediate-release:

One immediate-release 25 mg tablet three times daily, one hour before meals, and in midevening if desired to overcome night hunger.

Diethylpropion hydrochloride controlled-release:

One controlled-release 75 mg tablet daily, swallowed whole, in midmorning.

Geriatric Use:

This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. (See PRECAUTIONS, Geriatric Use.)

Side effects, and when to stop

Cardiovascular: Precordial pain, arrhythmia (including ventricular), ECG changes, tachycardia, elevation of blood pressure, palpitation and rare reports of pulmonary hypertension. Valvular heart disease associated with the use of some anorectic agents such as fenfluramine and dexfenfluramine, both independently and especially when used in combination, have been reported. Valvulopathy has been very rarely reported with diethylpropion hydrochloride monotherapy, but the causal relationship remains uncertain.

Central Nervous System: In a few epileptics an increase in convulsive episodes has been reported; rarely psychotic episodes at recommended doses; dyskinesia, blurred vision, overstimulation, nervousness, restlessness, dizziness, jitteriness, insomnia, anxiety, euphoria, depression, dysphoria, tremor, mydriasis, drowsiness, malaise, headache, and cerebrovascular accident

Gastrointestinal: Vomiting, diarrhea, abdominal discomfort, dryness of the mouth, unpleasant taste, nausea, constipation, other gastrointestinal disturbances

Allergic: Urticaria, rash, ecchymosis, erythema

Endocrine: Impotence, changes in libido, gynecomastia, menstrual upset

Hematopoietic System: Bone marrow depression, agranulocytosis, leukopenia

Miscellaneous: A variety of miscellaneous adverse reactions has been reported by physicians. These include complaints such as dysuria, dyspnea, hair loss, muscle pain, increased sweating, and polyuria.

Who should not take it

Pulmonary hypertension, advanced arteriosclerosis, hyperthyroidism, known hypersensitivity or idiosyncrasy to the sympathomimetic amines, glaucoma, severe hypertension. (See PRECAUTIONS.)

Agitated states.

Patients with a history of drug abuse.

Use in combination with other anorectic agents is contraindicated.

During or within 14 days following the administration of monoamine oxidase inhibitors, hypertensive crises may result.

Warnings

Diethylpropion hydrochloride should not be used in combination with other anorectic agents, including prescribed drugs, over-the-counter preparations, and herbal products.

In a case-control epidemiological study, the use of anorectic agents, including diethylpropion, was associated with an increased risk of developing pulmonary hypertension, a rare, but often fatal disorder. The use of anorectic agents for longer than 3 months was associated with a 23-fold increase in the risk of developing pulmonary hypertension. Increased risk of pulmonary hypertension with repeated courses of therapy cannot be excluded.

The onset or aggravation of exertional dyspnea, or unexplained symptoms of angina pectoris, syncope, or lower extremity edema suggest the possibility of occurrence of pulmonary hypertension. Under these circumstances, diethylpropion hydrochloride should be immediately discontinued, and the patient should be evaluated for the possible presence of pulmonary hypertension.

Valvular heart disease associated with the use of some anorectic agents such as fenfluramine and dexfenfluramine has been reported. Possible contributing factors include use for extended periods of time, higher than recommended dose, and/or use in combination with other anorectic drugs. Valvulopathy has been very rarely reported with diethylpropion hydrochloride monotherapy, but the causal relationship remains uncertain. The potential risk of possible serious adverse effects such as valvular heart disease and pulmonary hypertension should be assessed carefully against the potential benefit of weight loss. Baseline cardiac evaluation should be considered to detect preexisting valvular heart diseases or pulmonary hypertension prior to initiation of diethylpropion hydrochloride treatment. Diethylpropion hydrochloride is not recommended in patients with known heart murmur or valvular heart disease. Echocardiogram during and after treatment could be useful for detecting any valvular disorders which may occur.

To limit unwarranted exposure and risks, treatment with diethylpropion hydrochloride should be continued only if the patient has satisfactory weight loss within the first 4 weeks of treatment (e.g., weight loss of at least 4 pounds, or as determined by the physician and patient).

Diethylpropion hydrochloride is not recommended for patients who used any anorectic agents within the prior year.

If tolerance develops, the recommended dose should not be exceeded in an attempt to increase the effect; rather, the drug should be discontinued. Diethylpropion hydrochloride may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle; the patient should therefore be cautioned accordingly.

Prolonged use of diethylpropion hydrochloride may induce dependence with withdrawal syndrome on cessation of therapy. Hallucinations have occurred rarely following high doses of the drug. Several cases of toxic psychosis have been reported following the excessive use of the drug and some have been reported in which the recommended dose appears not to have been exceeded. Psychosis abated after the drug was discontinued.

When central nervous system active agents are used, consideration must always be given to the possibility of adverse interactions with alcohol.

Other medicines and interactions

Because diethylpropion hydrochloride is a monoamine, hypertension may result when this agent is used with monoamine oxidase (MAO) inhibitors (see CONTRAINDICATIONS ).

Efficacy of diethylpropion with other anorectic agents has not been studied and the combined use may have the potential for serious cardiac problems; therefore, the concomitant use with other anorectic agents is contraindicated.

Antidiabetic drug requirements (i.e., insulin) may be altered. Concurrent use with general anesthetics may result in arrhythmias. The pressor effects of diethylpropion and those of other drugs may be additive when the drugs are used concomitantly; conversely, diethylpropion may interfere with antihypertensive drugs (i.e., guanethidine, α-methyldopa). Concurrent use of phenothiazines may antagonize the anorectic effect of diethylpropion.

General

Caution is to be exercised in prescribing diethylpropion hydrochloride for patients with hypertension or with symptomatic cardiovascular disease, including arrhythmias. Diethylpropion hydrochloride should not be administered to patients with severe hypertension.

Reports suggest that diethylpropion hydrochloride may increase convulsions in some epileptics. Therefore, epileptics receiving diethylpropion hydrochloride should be carefully monitored. Titration of dose or discontinuance of diethylpropion hydrochloride may be necessary.

The least amount feasible should be prescribed or dispensed at one time in order to minimize the possibility of overdosage.